Clinical characteristics and laboratory findings in prion diseases

Acutely progressing dementia, generalized myoclonus, and periodic synchronous discharge (PSD) on EEG are thought to be characteristic features of Creutzfeldt-Jakob disease (CJD). However, recent surveillance studies in European countries and Japan have revealed several uncommon variants that run relatively long clinical course, demonstrate atypical myoclonus, and show no PSD. Brain specific proteins such as 14-3-3 protein, tau protein, and neuron specific enolase (NSE) are detected in the CSF of CJD patients. Clinical features and laboratory findings of sporadic CJD are related well to the combination of polymorphism at codon 129 of prion protein gene(PRNP) (Methionine/Methionine, Methionine/Valine, and Valine/Valine) and type of pathogenic prion protein (type 1 and type 2). Those of genetic prion disease depend on pathogenic mutation in PRNP. Positive rates of PSD and 14-3-3 protein in the CSF differ among subtypes of sporadic CJD and genetic prion diseases. Diffusion-weighted MRI is very useful for an early clinical diagnosis of CJD and some subtypes show their own characteristic findings.